Surprising Nanostructures Found on Guillemots Eggs May Impact Human Invention

Guillemots, birds famous for nesting on rock ledges and exposed cliffs, are born from eggs that are not only designed to keep them from tumbling down the mountainside, but are self-cleaning, according to a new study.

Presented at the Society for Experimental Biology Conference held in Spain, lead researcher Steven Portugal from the Royal Veterinary College in London said he first realized something was different about the eggs when water was spilled over an egg collection. As this happened, the water collected on the guillemot eggs in a manner that differed from all the others.

"The water droplets stayed as a sphere on the eggs, typically an indication of a hydrophobic surface," Portugal said in a press release.

Along with his colleagues, Portugal ran a series of tests on guillemot eggs that revealed a number of unique nanostructures, including a higher water contact angle, or the angle between a surface and the top of a water droplet as it beads up, which in turn makes it less likely to be absorbed. This sturcture also means is the eggs are able to stay clean all on their own as water moves quickly off its surface, taking dirt with it.

The guillemot eggs in the study also boasted significantly rougher surfaces to help to prevent them from falling off a cliff or out of their parents' feet and a higher rate of gaseous exchange to enable the eggs to cope with the high salt content from the sea spray.

In a comparative study of over 400 species, these structures proved to be unique to guillemot eggshells and those closely related to the guillemots. Similar hydrophobic nano-structures have been identified in the lotus leaf, however, and have been mimicked by humans in certain industries.

"Guillemots are unusual in that they don't bother with a nest at all, they just dump the eggs on the cliff face," Portugal explained to BBC News. "And they're crowded into these dense colonies. So they need to have a mechanism for coping with the salt spray coming off the sea and for dealing with the face that there's a lot of detritus around [from the other birds]. That's what these structures do."

Ultimately, the researchers believe the new findings may soon have an important impact in the emerging field of biomimetics, the imitation of nature in human-made processes, substances, devices or systems.